The most common and most likely answer to this crossword clue is the 9 letter word SECTIONED
I've seen this crossword clue in The Daily Telegraph
S
E
C
T
I
O
N
E
D
Buddy explains!
The straight part
We know that "in parts" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case in parts = sectioned.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SECTIONED mean?
SECTIONED verb- To cut, divide or separate into pieces.
- To reduce to the degree of thinness required for study with the microscope.
- To commit (a person, to a hospital, with or without their consent), as for mental health reasons. So called after various sections of legal acts regarding mental health.
- Medical To perform a cesarean section on (someone).